Method of forming twisted chain links



p 1939- G. s. SCHMIDT, JR' I 2,171,995v

METHOD OF FORMING TWISTED CHAIN LINKS Filed July 2, 1936 )ATTORNEYPatented Sept. 5, 1939 UNITED STATES IVIETHOD OF liORllllIlNG TWISTEDCHAIN LINKS George Small Schmidt, Jr., York, Pa.,

to American Chain 85 Cable Company,

assignor Inc.,

a corporation of New York Application July 2, 1936, Serial No. 88,547

'7 Claims.

The present invention relates to a novel method of forming twisted chainlinks such as curb links and the like.

I-Ieretofore, it has been the practice to make such links in the form offiat closed loops and then to twist opposite ends of each link inopposite directions. In the ordinary curb link it is desirable toprovide a twist of about 90 degrees. In other words, the plane of oneend of the link is disposed substantially at right angles to the planeof the other end. There are other forms of links in which such relationof the opposite ends of the links must be carried to a greater angulardegree. For example, in Letters Patent of the United States granted toJohn R. Reyburn, No. 2,053,047 dated September 1, 1936, there isdisclosed a link particularly adapted for use in cross chains applied totraction wheels in which the angular relation of the opposite ends maybe anywhere from 100 to 180 degrees, while the side elements of the linkare widely spaced apart. In the ordinary process of forming curb links,as the opposite ends are relatively twisted the sides of the link aregradually drawn together and if the twisting is carried far enough thesides are brought into actual contact with each other.

An object of the present invention is to provide a method of and meansfor forming twisted chain links without causing the side elements of thelink to move inwardly toward each other.

Another object of the present invention is to provide a method offorming a twisted link or a chain of such links without subjecting theopposite ends of the link to relative torsion.

With the above-named objects in view and such others that may appearhereinafter I shall now describe my improved method and a preferredembodiment of the means for carrying out said method and thereafter thenovelty and scope of the invention will be set forth in the claims.

In the acompanying drawing;

Figure 1 is a plan View of a link before being subjected to my novelforming method;

Figs. 2, 3 and 4 show a chain of links formed by my process,illustrating the links in plan, side elevation and end elevation,respectively;

Fig. 5 is a plan view of part of the means for forming the links; and

Fig. 6 is a view in side elevation of the link forming means.

I have discovered that a so-called twisted link may be formed by asimple bending process without applying a torsional twist to oppositeends of the link, thus avoiding the crowding of the side elements of thelink toward each other even though the relative angular relation of theopposite ends of the link be carried up to 180 degrees. I have foundthat if a link in the form of a flat oblong loop be bent transverselybut on an axis that is disposed obliquely with respect to the major axisof the loop, the result will be a link which has the appearance ofhaving been twistedexcept that the sides of the link will remain inwidely spaced relation; also that the relative angularity of theopposite ends of the link may be varied in accordance with the obliquityof the axis of the bend with respect to the original major axis of thelink.

In Figure l, I show a flat link I!) in the form of an elongated loopcomprising a pair of parallel side elements H which are connected by apair of semi-circular end elements l2. The major axis of the link beforebending is indicated by the line A-A. In order to convert this flat linkinto a twisted link it is bent transversely about an axis B-B which isobliquely disposed with respect to the axis A-A. This causes a shift ofthe major axis in the bent link to the line C-C which is the line ofpull of a chain of such links. In plan the link will have asubstantially diamond shaped appearance, as shown in Fig. 2, with twoopposite sides convex and the the other two sides concave. In the linksillustrated in Figs. 2 to 4 inclusive, these sides are all approximatelysemi-circles and in side elevation as well as in end elevation the linkshave the projected form of the figure 3. The figure 8 is obviouslylonger in Fig. 3 than in Fig. 4 because the links are longer than theyare wide but otherwise they are quite symmetrical.

Viewedendwise, that is, in the direction of the axis C -C, it will beobserved that one end of the link lies in the plane DD, while theopposite end of the link lies in the plane E--E and in the particularlink illustrated, these planes form an angle of approximately 120degrees to each other. In other words, a structure is obtained whichcorresponds to a link whose opposite ends have been relatively twisted120 degrees, with this important difference, however, that because of mymethod of forming the links the side elements are not drawn together butremain in widely spaced relation to each other. Obviously, theangularity of one end with respect to the other may be increased ordecreased by correspondingly increasing or decreasing the depth of thebend. In the particular link illustrated, the axis B-B forms an angle ofabout degrees with the axis AA. If this angle is decreased there will bea smaller angular. departure of axis C-C from axis A-A and the bent linkwill be longer.

A convenient means of carrying out my forming method is illustrated inFigs. 5 and 6. I show at l5 a die having the shape of a substantiallysemi-cylindrical trough. However, the depth and form of the trough maybe varied in accordance with the desired shape of the bent link. The dieis formed with flat shoulders I6 and H disposed respectively at oppositesides of the trough and these shoulders have rounded edges where theymerge into the trough. Projecting, from each shoulder is a pair of pinsl8 which serve to position the link on the die. It will be observed thatthe position of the pins on the shoulder ll is advanced with respect tothe po-.

sition of the pins on the shoulder 16 so that when a link IE] is bridgedacross the trough it will be positioned by these pins at the desiredangle with respect to the die. In order to permit of form ing the linksof a chain after they have been interlinked the die block is formed witha. recess 20 to receive the link that is to be bent next and a similarnotch 2! is formed in the shoulder IT to receive a link that has alreadybeen bent. Cooperating with the die 15 is .a punch 22 which is in theform of a blade adapted to force the link downward between the shouldersinto the trough of the die. This punch is provided with a cylindricallyrounded lower end corresponding in general to the curvature of thetrough and is also provided with slots 23 and 243 in opposite sidesthereof to clear the links which may be lying in the recesses 2|] and 21respectively. The punch and die are preferably operated in a punchpress, although obviously my method could be carried out by any power ormanual means for causing relative movement of the punch and die.

The term twisted link as used in the foregoing specification and also inthe claims will be understood to refer to a link which has theappearance of having been twisted although actual twisting is avoided bymy method. It will be understood that the side elements of a link formedby my process may be truly helical if the proper form of die and punchis used and in this respect the links would then differ from theordinary curb link in which the side elements do not consist of parallelhelices.

While I have described a preferred embodiment of the means for carryingout my process it will be understood that this is to be taken asillustrative and not limitative of my invention and that I reserve theright to make various changes in form, construction, and arrangement ofparts without departing from the spirit and scope of my invention asdefined in the following claims. It will also be understood that theform of the original fiat link is not limited by the showing in Fig. 1and that while in said figure the side elements correspond in lengthsubstantially to the end elements so that after the link has been bentall of the curved parts "twisted link out of an oblong flat link whichconsists in bending the flat link into helically distorted U-form byapplying a bending force thereto in a direction normal to the plane ofthe flat link at points on a line disposed obliquely with respect to themajor axis of the fiat link.

3. The method of forming a link simulating a twisted link which consistsin making an oblong flat loop, and bending this loop into helicallydistorted U-form by applying a bending force thereto in a directionnormal to the plane of the fiat loop at points on a line disposedobliquely with respect to the major axis of the flat loop.

4. The method of forming a link simulating a twisted link out of anoblong flat link which consists in bending said fiat link cylindricallyabout the line of intersection of a plane extending parallel to theplane of said flat link .and a plane normal to the plane of said fiatlink and intersecting the major axis of said fiat link.

5. The method of forming a link simulating a twisted link out of anelongated flat loop which consists in bendingthe side strands of saidloop into helical paths about a common axis lying in a plane extendingnormal to said flat loop and intersecting the major axis of said flatloop.

6. The method of forming a link composed of a closed loop of metallicwire of substantially saddle form with substantially parallel arcuateside elements and substantially parallel arcuate end elements, all ofsaid arcuate elements being of substantially the same radius but withthe axis of the side elements forming an acute angle with the axis ofthe end elements, which consists in bending an elongated flat loophaving'parallel side strands and semi-circular ends into a helicallydistorted U-form.

7. The method of forming a link composed of .a closed loop of metallicwire of substantially saddle like form with substantially parallelarcuate side elements and substantially parallel arcuate end elements,all of said elements being of substantially the same radius, whichconsists in bending an elongated flat loop having parallel side strandsand semi-circular ends cylindrically about an axis lying in a planeparallel to the plane of the loop and extending at an angle with respectto the major axis of the flat loop.

GEORGE SMALL SCHMIDT, JR.

